Document controlled picking and feeding apparatus

ABSTRACT

A VACCUM ACTUATED DOCUMENT PICKING AND FEEDING MECHANISM WHEREIN THE DOCUMENT ACTS AS A VALVE BY CLOSING OPENINGS IN A STATIONARY SUCTION ROLLER THEREBY CAUSING A DOCUMENT DEED CYCLE TO BE INITIATED DURING WHICH THE DOCUMENT IS INITIALLY LIFTED AND THEREAFTER DRIVEN UNTIL THE DOCUMENT IS DELIVERED FROM SUCTION ROLLER CONTACT. UNCOVERING THE VACUUM OPENINGS IN THE SUCTION ROLLER ACTS TO DISCONTINUE THE DRIVING CONNECTION WHIT THE DRIVE MECHANISM AND PERMIT RESTORATION OF THE ROLLER ASSEMBLY TO AN INITIAL POSITION THEREBY ALSO PERMITTING USE OF A FEEDBACK FUNCTION.   D R A W I N G

nited States Patent [1 91 Lorensen et al. v

DOCUMENT CONTROLLED PICKING AND FEEDING APPARATUS Inventors: Cletus E. Lorensen, Rochester:

John A. Peterson. New Brighton. both of Minn Assignee: International Business Machines Corporation, Armonk, N.Y.

Filed: May 21,1971

Appl. No.: 145,668

US. Cl. .f. 271/27 Int. Cl B65h 3/08 Field of Search References Cited UNITED STATES PATENTS Spiess 271/27 Jan. 22, 1974 Primary Examiner-Edward A. Sroka Attorneyl-lanifin and Jancin and M. H. Klitzman [57] ABSTRACT A vacuum actuated document picking and feeding mechanism wherein the document acts as a valve by closing openings in a stationary suction roller thereby causing a document feed cycle to be initiated during which the document is initially lifted and thereafter driven until the document is delivered from suction roller contact. Uncovering the vacuum openings in the suction roller acts to discontinue the driving connection with the drive mechanism and permit restoration of the roller assembly to an initial position thereby also permitting use of a feedback function.

4 Claims, 5 Drawing Figures PAIEMED BQTBTLOM SHUZI 1 UF 2 FIG. 2

PATENTED M22 3, 7'87, 044

SHEEY 2 BF 2 VACUUM SOURCE "7 DOCUMENT CONTROLLED PICKING AND FEEDING APPARATUS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an apparatus for pneumatically picking and feeding documents singularly from a stack. More specifically, the invention relates to a defrom the stack, the sheet was fed forward in various ways. This type of prior art device is not suitable for picking and feeding sheets with printed matter thereon at high speeds because the friction between the sheet and the nozzle surface when removing the sheets from the picker slows down the sheet feeding operation and also causes smearing of the printed matter on the sheets.

Another prior art device lifts the topmost sheet from a stack by a suction roller or vacuum wheel being brought into contact with a second rotating suction roller to feed the sheet forward. This prior art device improves the sheet feeding operation because the frictional resistance at the point of contact between the sheet and the suction device is reduced due to the suction roller rotating to follow the sheet. While this reduction of frictional resistance allows for higher speeds and for less smearing of printing on the sheets, some amount of relative movement takes place between the sheet and the two suction rollers due to any slight difference in rotating speeds of the rollers. Both of these prior art devices begin to feed the sheets after the sheet has been completely lifted by the picking means into contact with another means for further feeding the sheet forward, thus wasting time in the overall feeding cycle. Additionally, neither of these prior art devices eliminates smearing of printed matter on the sheets because some relative movement or friction is still existent between the picking and feeding means used.

It is, therefore, an object of the present invention to pick and concurrently feed sheets from a stack at high speeds.

It is another object of this invention to pick and feed sheets from a. stack in an improved'manner, so as to eliminate the relative movement between the sheet and the picking and feeding mechanism.

SUMMARY STATEMENT In order to carry out the objects of. this invention, as stated above, we provide a sheet picking and feeding apparatus wherein the sheet actuates both the lifting and feeding of the document. The concurrent lifting For the purposes of this application, the term suction roller includes any rotatably mounted device which can attract sheets, such as a suction cylinder.

The advantage of such apparatus is that it allows sheets to be sequentially picked and fed from a stack at high speeds while preventing any smearing of the printed matter on the sheets.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of the preferred embodiment of the invention, as illustrated in the accompanying drawings.

IN THE DRAWINGS FIG. 1 shows a side elevation of the bellows-lever mechanism at a stage of a cycle where it is in position to pick a sheet from the stack.

FIG. 2 is a partial side elevation showing the picking and feeding mechanism of FIG. I at a stage during feeding when the picker is being lifted.

FIG. 3 shows a side elevation of the picking and feeding mechanism of FIG. 1 at a stage during feeding when the picker has been lifted to contact the limiting abutment.

FIG. 4 shows an elevation of the bellows-lever mechanism and drive therefore partly in section and partly broken away.

FIG. 5 shows a section view of the suction roller with an internal suction shoe shown along section 5 of FIG. 4.

DETAILED DESCRIPTION In the preferred embodiment of the invention, as shown in FIG. 1, a rotatable suction roller 26 attracts the topmost sheet from a stack of sheets 62. Attached to roller 26 is a concurrent raising or lifting and rotating meanswhich, in response to topmost sheet 60 adhering to roller 26, causes roller 26 to begin rising and to rotate.

The concurrent picking and feeding means, for purposes of this specification and as shown in the preferred embodiment, consists generally of a drive means and raising means which are concurrently actuated due to a change in air pressure caused bythe sheet 60 adhering to roller 26 and acting as a valve. Also for purposes of this specification, the drive means of the preferred embodiment, consists generally of vacuum clutch 48, axle 46,- pulley 50, drive belt 52,.pulley 54 and axle 28 which all act together to drive: roller 26. Also the raising means in the preferred embodiment includes gener-' ally shoe 4], connectingmeans 40, retractable means 16 and vacuum source 10 which all cooperate to raise roller 26 when sheet 60 adheres thereto.

Vacuum source 10 provides suction for this sheet picking and feeding device. Vacuum source 10 draws suction through conduit 22 which is connected to be]- lows 16 by flange l4. Flange 14. is fixed so that the movement of the picking andfeeding device takes place below it. 1

The bellows 16'forms a retractable means and responds to an increase in partial vacuum brought about means for connecting the vacuum source to the surface of suction roller 26 is designated generally as connecting means 40.

Connecting means 40 connects bellows 18 to axle 28 and supports suction roller 26. Connecting means 40 also includes extending arm 24 so that the suction roller 26 will pivot about axle 46 when raised and lowered. In the preferred embodiment, connecting means 40 also provides the conduit through which the vacuum source 10 can operate. Suction shoe 41 is the lower end of connecting means 40 and provides a lower conduit 42 which is connected to upper conduit 22. Connecting means 40 supports axle 28 with two sets of bearings 44. Axle 28 is thus caused to be raised and lowered by connecting means 40 when a change in pressure actuates bellows 16. Axle 28 in turn supports suction roller 26.

As shown in FIG. 4, suction roller 26 is connected to axle 28 by nut 30 and washer 32. Roller 26 has suction openings or slots disposed along the circumference in a radial plane, one of such slots being denoted by numeral 34. Suction roller 26 is shown with a foam covering 38 to provide a high friction surface and to provide a cushion when the roller 26 is lowered into contact with the topmost sheet 60. When a sheet 60 contacts the surface of suction roller 26 and cuts off the air supply through the slots 34, and the port 36 of shoe 4], a partial vacuum is created in the conduits and bellows 16. The partial vacuum created causes bellows 16 to collapse which in turn causes the suction roller 26 and thereby sheet 60 to be raised.

A drive means for rotating suction roller 26 is connected to roller 26 by axle 28 being fixedly attached thereto. The drive means is actuated by the change in pressure at the same time that the bellows 16 is actuated, so that the lifting and driving of the sheet occur concurrently. A change in pressure caused by sheet 60 adhering to the suction roller actuates vacuum clutch 48 which is connected through conduit 22. A vacuum clutch is well-known in the prior art and therefore is not shown in more detail. Vacuum clutch 48, when actuated, drives axle 46 and thereby pulley 50. Drive belt 52 is connected from pulley 50 to pulley 54 which is in turn is attached to axle 28, thus causing the suction roller 26 to rotate.

The fixed abutment 56 is positioned in the path of the assembly carrying roller 26 and prevents flange from rising above a certain point; In this way, equal spacing can be maintained between the sheets being picked.

Sheet stiffening and suction roller cushioning are both provided for by two leaf springs 58 connected to the arm 24 and biased toward the stack of sheets 62. The leaf springs 58 act as a means to stiffen the sheet being picked and fed by causing the topmost sheet 60 to form a cup-like shape between the leaf springs 58. In this way, the sheet 60 is able to be forwardly fed at a high rate of speed. Leaf springs 58 also further cushion the lowering of the suction roller 26 onto the topmost sheet 60. They also aid in accelerating the suction roller when being raised by releasing the energy stored in the spring when it was acting as a cushioning means.

OPERATION The detailed operation of the preferred embodiment will be described beginning with the suction roller 26 being stationary at the bottom of its cycle, where it will attract the topmost sheet 60 from the stack 62 as shown in FIG. 1. When sheet is attracted to the surface of roller 26, the port 36 of suction shoe 41 is blocked, thus, creating an increase in partial vacuum through the conduits and bellows 16. Since, bellows 16 is fixed at the top of flange 14, the change in partial vacuum will cause the bottom of bellows 16 to rise. Since bellows 16 is connected to suction roller 26 by connecting means 40 and axle 28, the roller 26 along with the topmost sheet 60 will also be raised. At the same time as suction roller 26 begins to be raised, the change in partial vacuum created by the sheet 60-adhering to the roller 26 causes vacuum clutch 48 to drive axle 46 and thereby drive the topmost sheet 60 forward. As thus shown in FIG. 2, it is seen that the topmost sheet acting as a valve actuates the vacuum system to cause concurrent lifting and feeding of the sheets.

Suction cylinder 26 will rise the same distance each time because it will be stopped by abutment 56 until the backmost edge of sheet 60 clears port 36. This creates constant inter-document spacing of the fed sheets and allows sheets of different size to be fed from the same stack. 7

As shown in FIG. 3, when the topmost sheet 60 clears the edge of port 36, the vacuum level returns to its normal level causing vacuum clutch 48 to disengage axle 46 which in turn allows the system friction to stop roller 26 from rotating at the same time bellows l6 elongates. Since the driving means is disengaged as soon as the sheet 60 clears port 36, the roller 26 is completely at rest when it comes into position to pick the next sheet. This factor prevents the printed matter on the sheets from being smeared. When roller 26 gets to a point near the surface of the next sheet in stack 62, leaf springs 58 will contact the topmost sheet first. This will serve to cushion the lowering of the roller 26. Leaf springs 58 will also serve to provide an accelerating force when roller 26 begins to be raised again.

Although our preferred embodiment shows a bellows lifting mechanism, other mechanisms which can lift in response to a change in pressure can be used. A pistoncylinder or a diaphram have previously been used to respond to changes in pressure and thus, could be substituted for the bellows mechanism.

There are numerous advantages to the construction and use of our invention, which willbe obvious to anyone of skill in the art, the following, not by way of limitation, are noteworthy:

An advantage of this invention is that the sheet to be picked and fed actuates both the picking and feeding mechanism concurrently, thus, bringing about a positive control in the picking and feeding cycle and increasing the speed of the overall picking and feeding operation.

Another advantage of this invention is that the printed matter on the sheets is not smeared due to the same part acting as both the picking and the feed mechanism.

A still further advantage of this invention is that sheets are fed with a constant inter-sheet gap which is independent of sheet size, the result being that a stack of sheets of different size can be picked and fed from one stack at the same time.

While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it would be understood by those skilled in the art that the foregoing and other art changes in form and detail may be made therein without departing from the spirit and scope of the invention.

What is claimed is: 1. A device for picking and feeding sheets singularly from a stack comprising:

a rotatable suction roller for picking and feeding the sheets; retractable means connected to said roller being res'ponsive to change in pressure caused by each of the sheets adhering to said roller, said retractable means being activated to raise and lower the roller; drive means connected to said roller being responsive to change in pressure caused by each of the sheets adhering to said roller, said ,drive means being activated to rotate the roller concurrently with the activation of said retractable means, whereby each of said sheets is simultaneously picked and fed from the stack without relative movement between each of the sheets and the roller. 2. A device for picking and feeding sheets singularly from a stack comprising:

a rotatable suction roller fixedly attached to a rotatable axle for picking and feeding the sheets;

a vacuum source; retractable means connected to said vacuum source and said roller being responsive to change in pressure caused by each of said sheets adhering to said roller, said retractable means being activated to raise and lower the roller; connecting means positionedibetween the vacuum source and the roller for conveying vacuum to the surface of the roller, said connecting means supporting the axle so that the raising and lowering of said retractable means causes raising and lowering of the roller, said connecting means also having an extending arm to pivot the raising and lowering of said roller about a pivot point;

drive means connected to said roller being responsive to change in pressure caused by each of said sheets adhering to said roller, said drive means being activated to rotate the roller concurrently with the activation of said retractable means, said drive means further comprising:

a vacuum clutch attached to said connecting means being esponsive to change in pressure in said connecting means;

a pulley coaxial with said pivot point being driven periodically by said vacuum clutch;

a belt connected from said pulley to said axle to drive said axle and thereby said roller, whereby each of said sheets is simultaneously picked and fed from the stack with no relative movement between each of the sheets and the roller.

3. A sheet picking and feeding device as claimed in claim 1, further comprising a fixed abutment positioned to limit the travel of said roller induced by said picking and feeding means 'in order to maintain equal spacing between the sheets. 1

4. A sheet picking and feeding device as claimed in claim 3, further comprising two leaf springs attached to said extending arm and depending toward the stack of sheets, said leaf springs acting to stiffen each of said sheets for fast forwarding feeding, to cushion the lowering of the roller when near the sheets and to increase the lifting speed of the suction roller. 

